Radio working and then put away , stored indoors for some years.
Now only strong AM signals come through with a decent aerial.
The IC functions as far as remote tuning via varicap , AGC , S meter, but
what could decrease the RF gain just sitting around unused ?
I have the Sanyo datasheet and DC supply to the RF section is correct

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

"N_Cook" wrote in news:g1e72n$ei0$1
@registered.motzarella.org:

Radio working and then put away , stored indoors for some years.
Now only strong AM signals come through with a decent aerial.
The IC functions as far as remote tuning via varicap , AGC , S meter, but
what could decrease the RF gain just sitting around unused ?
I have the Sanyo datasheet and DC supply to the RF section is correct

Possibly capacitor aging. Ceramic capacitors 'AGE' (decline in capacitance
with time)
High K ceramic capacitors 'age' at a higher percentage rate than low K
capacitors, so ceramic 'bypass' capacitors can decline in value with time.

You could 'deage' the capacitors by heating the radio above the ceramics
Curi point.
see http://www.johansondielectrics.com/technicalnotes/age/

If you stored in humid conditions, fungus could grow, metals corrode,
electrolysis form paths across circuit boards.
All of those can effect gain also.



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap

N_Cook schrieb:

Radio working and then put away , stored indoors for some years.
Now only strong AM signals come through with a decent aerial.
The IC functions as far as remote tuning via varicap , AGC , S meter, but
what could decrease the RF gain just sitting around unused ?

Have a look at C 102 (47 nF at pin 2).

HTH

Reinhard

Radio working and then put away , stored indoors for some years.
Now only strong AM signals come through with a decent aerial.
The IC functions as far as remote tuning via varicap , AGC , S meter, but
what could decrease the RF gain just sitting around unused ?
I have the Sanyo datasheet and DC supply to the RF section is correct

Maybe a bad voltage into pin 17 (AGC input)? Possibly one of the
filter electrolytics on the detector-to-AGC path has dried out or gone
open?

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!